270 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



the first in length, or a little shorter, flattened, somewhat lanceolate, 

 attenuated at the end ; terminal style none (in E. marginatus 9 , the 

 antennse are a little longer than the head, and the first joint is dis- 

 tinctly longer than the third). 



Thorax but little convex ; its dorsum, in E. funestus, luctifer y har- 

 risii, and murieatus , of which I have only male specimens, is beset with 

 minute, rigid, sharp, conical points, arranged in irregular rows. As E, 

 marginatus and magnus, of which I have only females, do not have these 

 points, it seems very probable that this is a sexual character. 



Seutellum comparatively large, almost semicircular, convex, cushion- 

 shaped. 



Abdomen cylindrical, long and slender, by one-half longer than head 

 and thorax taken together ; in the male, eight segments, the genitals 

 forming the ninth ; in the females of E. marginatus and magnus, I count 

 only seven segments besides that bearing the genitals. 



Legs long and slender, beset with sparse spiuules along the tibiae 5 hind 

 legs by far the longest ; pulvilli distinct, rather broad ; ungues curved, 

 broad at base. In my female specimens, I perceive a few stiff spine-like 

 bristles on the under side of the hind femora, two in E. marginatus ; four 

 or five in E. magnus. I do not see anything like it in the males. 



Wings but little shorter than the body, rather narrow, attenuated at 

 the base ; alula small, very narrow. In E. murieatus, the wings are 

 broader. 



Venation. — Two submarginal and four posterior cells ; first posterior 

 broadly open; upper branch of third vein gently S-shaped, inserted about 

 the middle of the section of that vein beyond the small cross- vein. The lat- 

 ter corresponds to the middle of the discal cell. Prsefurca less than half 

 as long as the distance between the bifurcation and the small cross- vein ; 

 second vein gently arcuated on its latter half, reaching the margin with- 

 out forming any sinus; thus the marginal cell is not expanded at its 

 end. The proximal end of the third posterior cell is opposite the small 

 cross-vein ; anal cell open (Mac-quart's figure, Dipt. Exot., ii, 1, tab. 11, 

 f. 1, gives a tolerably correct idea of the venation, except that the anal 

 cell is represented as being closed ; the upper branch of the thiid vein 

 in E. magnus and murieatus is nearly as bisinuate as represented, but- 

 it is less so in the other species). The costal margin in the male sex is 

 beset with minute blunt points, as in Ploas ; they are almost obsolete in 

 some species (E.funestus) ; very distinct in others (E. murieatus). 



In the following table I include Macquart's E. niger from the data in 

 his description : 



Wings infuscated, but anal angle (including at least the second basal, 

 anal, and axillary cells) hyaline : 

 Small species (7-8 mm long) : 



1. funestus ( <? ). — White Mountains, N. H. 

 Large species (12-14 mm long) : 



Prevailing pubescence black : 



5. magnus ( 9 ). — Vancouver Island. 





